[commands] Remove EndlessCommand (#4483)

Author: Starlight220

cpp/frc2/command/Command.cpp

@@ -7,7 +7,6 @@
 #include "frc2/command/CommandHelper.h"
 #include "frc2/command/CommandScheduler.h"
 #include "frc2/command/ConditionalCommand.h"
-#include "frc2/command/EndlessCommand.h"
 #include "frc2/command/InstantCommand.h"
 #include "frc2/command/ParallelCommandGroup.h"
 #include "frc2/command/ParallelDeadlineGroup.h"
@@ -91,10 +90,6 @@ PerpetualCommand Command::Perpetually() && {
   WPI_UNIGNORE_DEPRECATED
 }
 
-CommandPtr Command::Endlessly() && {
-  return CommandPtr(std::move(*this).TransferOwnership()).Endlessly();
-}
-
 CommandPtr Command::Repeatedly() && {
   return CommandPtr(std::move(*this).TransferOwnership()).Repeatedly();
 }

cpp/frc2/command/CommandPtr.cpp

@@ -6,7 +6,6 @@
 
 #include "frc2/command/CommandScheduler.h"
 #include "frc2/command/ConditionalCommand.h"
-#include "frc2/command/EndlessCommand.h"
 #include "frc2/command/InstantCommand.h"
 #include "frc2/command/ParallelCommandGroup.h"
 #include "frc2/command/ParallelDeadlineGroup.h"
@@ -26,11 +25,6 @@ CommandPtr CommandPtr::Repeatedly() && {
   return std::move(*this);
 }
 
-CommandPtr CommandPtr::Endlessly() && {
-  m_ptr = std::make_unique<EndlessCommand>(std::move(m_ptr));
-  return std::move(*this);
-}
-
 CommandPtr CommandPtr::AsProxy() && {
   m_ptr = std::make_unique<ProxyScheduleCommand>(std::move(m_ptr));
   return std::move(*this);

cpp/frc2/command/EndlessCommand.cpp

@@ -200,19 +200,21 @@ class Command {
    * conditions.  The decorated command can still be interrupted or canceled.
    *
    * @return the decorated command
-   * @deprecated replace with EndlessCommand
+   * @deprecated PerpetualCommand violates the assumption that execute() doesn't
+get called after isFinished() returns true -- an assumption that should be
+valid. This was unsafe/undefined behavior from the start, and RepeatCommand
+provides an easy way to achieve similar end results with slightly different (and
+safe) semantics.
    */
-  WPI_DEPRECATED("Replace with Endlessly()")
+  WPI_DEPRECATED(
+      "PerpetualCommand violates the assumption that execute() doesn't get "
+      "called after isFinished() returns true -- an assumption that should be "
+      "valid."
+      "This was unsafe/undefined behavior from the start, and RepeatCommand "
+      "provides an easy way to achieve similar end results with slightly "
+      "different (and safe) semantics.")
   PerpetualCommand Perpetually() &&;
 
-  /**
-   * Decorates this command to run endlessly, ignoring its ordinary end
-   * conditions. The decorated command can still be interrupted or canceled.
-   *
-   * @return the decorated command
-   */
-  [[nodiscard]] CommandPtr Endlessly() &&;
-
   /**
    * Decorates this command to run repeatedly, restarting it when it ends, until
    * this command is interrupted. The decorated command can still be canceled.

include/frc2/command/Command.h

@@ -46,14 +46,6 @@ class CommandPtr final {
    */
   [[nodiscard]] CommandPtr Repeatedly() &&;
 
-  /**
-   * Decorates this command to run endlessly, ignoring its ordinary end
-   * conditions. The decorated command can still be interrupted or canceled.
-   *
-   * @return the decorated command
-   */
-  [[nodiscard]] CommandPtr Endlessly() &&;
-
   /**
    * Decorates this command to run "by proxy" by wrapping it in a
    * ProxyScheduleCommand. This is useful for "forking off" from command groups

include/frc2/command/CommandPtr.h

@@ -29,7 +29,11 @@ namespace frc2 {
  *
  * This class is provided by the NewCommands VendorDep
  *
- * @deprecated replace with EndlessCommand
+ * @deprecated PerpetualCommand violates the assumption that execute() doesn't
+get called after isFinished() returns true -- an assumption that should be
+valid. This was unsafe/undefined behavior from the start, and RepeatCommand
+provides an easy way to achieve similar end results with slightly different (and
+safe) semantics.
  */
 class PerpetualCommand : public CommandHelper<CommandBase, PerpetualCommand> {
  public:
@@ -40,10 +44,16 @@ class PerpetualCommand : public CommandHelper<CommandBase, PerpetualCommand> {
    *
    * @param command the command to run perpetually
    */
-  WPI_DEPRECATED("Replace with EndlessCommand")
+  WPI_DEPRECATED(
+      "PerpetualCommand violates the assumption that execute() doesn't get "
+      "called after isFinished() returns true -- an assumption that should be "
+      "valid."
+      "This was unsafe/undefined behavior from the start, and RepeatCommand "
+      "provides an easy way to achieve similar end results with slightly "
+      "different (and safe) semantics.")
   explicit PerpetualCommand(std::unique_ptr<Command>&& command);
-
   WPI_IGNORE_DEPRECATED
+
   /**
    * Creates a new PerpetualCommand.  Will run another command in perpetuity,
    * ignoring that command's end conditions, unless this command itself is
@@ -53,7 +63,13 @@ class PerpetualCommand : public CommandHelper<CommandBase, PerpetualCommand> {
    */
   template <class T, typename = std::enable_if_t<std::is_base_of_v<
                          Command, std::remove_reference_t<T>>>>
-  WPI_DEPRECATED("Replace with EndlessCommand")
+  WPI_DEPRECATED(
+      "PerpetualCommand violates the assumption that execute() doesn't get "
+      "called after isFinished() returns true -- an assumption that should be "
+      "valid."
+      "This was unsafe/undefined behavior from the start, and RepeatCommand "
+      "provides an easy way to achieve similar end results with slightly "
+      "different (and safe) semantics.")
   explicit PerpetualCommand(T&& command)
       : PerpetualCommand(std::make_unique<std::remove_reference_t<T>>(
             std::forward<T>(command))) {}